Linear actuators are well-known components for use in machines and control devices, not at least they are widely used within the hospital and care sectors, where they are used for adjustable furniture such as patient lifting devices, beds etc. In this kind of applications, the linear actuator transfers a force between the attachment points of the actuator.
The construction of linear actuators, which can transfer the forces between the two attachment points without overloading the transmission and thus causing wearing, is difficult and often results in the construction being complicated and expensive. Further it mostly is more voluminous than desired. This is particularly the case where the linear actuator is equipped with a transmission, which comprises a planetary gear, since the configuration of a worm gear driving the sun gear of the planetary gear, will always result in a motor orientation perpendicular to the actuator main axis.
WO 98/30816, U.S. Pat. Nos. 8,410,731 and 8,308,603 disclose linear actuators where the transmission comprises a planetary gear, e.g. implying many components. Many components mean more expenses for material and production and that the linear actuator becomes voluminous.
The purpose of the invention is to provide a solution to the outlined problem, i.e. to achieve a linear actuator which is capable of leading the axial forces in the actuator around the transmission and that is cost-efficient, and that may provide a more compact and/or simple construction.